U.S. patent number 6,554,092 [Application Number 09/986,379] was granted by the patent office on 2003-04-29 for seatbelt device.
This patent grant is currently assigned to NSK Autoliv Co., Ltd.. Invention is credited to Masuo Matsuki, Yukinori Midorikawa, Katsuyasu Ono.
United States Patent |
6,554,092 |
Midorikawa , et al. |
April 29, 2003 |
Seatbelt device
Abstract
Provided is a seatbelt device capable of realizing a comfortable
seatbelt-wearing environment as well as appropriately securing and
protecting a passenger. The seatbelt device is further capable of
realizing an immediate escape or rescue of a passenger after a
vehicle accident, thereby providing extra safety and a swift escape
by protracting the webbing in accordance with the state of the
vehicle accident. This seatbelt device is provided with a retractor
which uses a motor for retracting and protracting the webbing that
secures a passenger to his/her seat, and a controller for rotating
the motor and at least retracting the webbing. The controller is
capable of altering the protraction mode of the webbing in
accordance with the state of the webbing fastened by the
passenger.
Inventors: |
Midorikawa; Yukinori (Fujisawa,
JP), Ono; Katsuyasu (Fujisawa, JP),
Matsuki; Masuo (Fujisawa, JP) |
Assignee: |
NSK Autoliv Co., Ltd.
(Fujisawa, JP)
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Family
ID: |
27324932 |
Appl.
No.: |
09/986,379 |
Filed: |
November 8, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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421872 |
Oct 21, 1999 |
6332629 |
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Foreign Application Priority Data
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Oct 23, 1998 [JP] |
|
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10-302088 |
Jun 25, 1999 [JP] |
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11-180957 |
Jul 1, 1999 [JP] |
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11-188256 |
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Current U.S.
Class: |
180/268; 180/272;
242/390.9; 280/807 |
Current CPC
Class: |
B60R
22/3416 (20130101); B60R 22/343 (20130101); B60R
22/44 (20130101); B60R 22/405 (20130101); B60R
22/415 (20130101); B60R 22/46 (20130101); B60R
2021/0016 (20130101); B60R 2022/4473 (20130101) |
Current International
Class: |
B60R
22/34 (20060101); B60R 22/343 (20060101); B60R
22/44 (20060101); B60R 22/46 (20060101); B60R
22/415 (20060101); B60R 21/00 (20060101); B60R
22/405 (20060101); B60R 022/34 (); B60R
022/48 () |
Field of
Search: |
;280/807,806
;180/268,272 ;242/390.9,390.8 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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6-71333 |
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Oct 1994 |
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JP |
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96/30235 |
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Oct 1996 |
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WO |
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Primary Examiner: English; Peter C.
Attorney, Agent or Firm: Crowell & Moring LLP
Parent Case Text
This application is a division of application Ser. No. 09/421,872,
filed Oct. 21, 1999, now U.S. Pat. No. 6,332,629.
Claims
What is claimed is:
1. A seatbelt device comprising: a retractor using a motor for
retracting and protracting a webbing that secures a passenger to a
seat; and a controller for rotating the motor in order to at least
retract the webbing and for generating an alarm; wherein the
controller executes a control program for setting a threshold value
of alarm generation, and executes either a protracting speed
program for determining a protraction speed of the webbing when the
passenger tries to fasten the seatbelt device, or a fastening time
program for determining a time required to fasten the seatbelt
device after a protraction of the webbing has stopped; wherein the
controller controls an ease of alarm generation by altering the
threshold value on a basis of at least either the speed determined
by the protracting speed program or the time determined by the
fastening time program.
2. The seatbelt device according to claim 1, wherein the controller
generates the alarm by rotating the motor to alternately and
repeatedly protract and retract the webbing.
3. The seatbelt device according to claim 1, having a buckle
connection detector for detecting a state of connection between a
buckle and a tongue, thereby detecting whether the webbing is
fastened or not.
4. A seatbelt device comprising: a retractor using a motor for
retracting and protracting a webbing that secures a passenger to a
seat; and a controller for rotating the motor in order to at least
retract the webbing and for generating an alarm; wherein the
controller executes a control program for setting a threshold value
of alarm generation, and executes a protraction frequency program
for determining a webbing protraction frequency while the seatbelt
device is fastened; wherein the controller controls an ease of
alarm generation by altering the threshold value on a basis of the
protraction frequency determined by the frequency program.
5. The seatbelt device according to claim 4, wherein the controller
generates the alarm by rotating the motor to alternately and
repeatedly protract and retract the webbing.
6. The seatbelt device according to claim 4, having a buckle
connection detector for detecting a state of connection between a
buckle and a tongue, wherein the protraction frequency is a value
obtained by dividing a number of times of webbing protraction by a
fastened-state duration after a buckle connection is detected by
the buckle connection detector.
7. A seatbelt device comprising: a retractor using a motor for
retracting and protracting a webbing that secures a passenger to a
seat; a first controller for rotating the motor in order to at
least retract the webbing; and a second controller for either
generating a collision danger alarm when a distance between a
vehicle of the passenger and an object ahead becomes less than a
specified value or a dozing alarm by determining an indication of
dozing by the passenger of the vehicle; wherein the first
controller alters an amount of slack of the webbing while the
webbing is fastened, on a basis of a number of alarm generation
times with regard to at least either the collision danger alarm or
the dozing alarm.
8. A seatbelt device comprising: a retractor using a motor for
retracting and protracting a webbing that secures a passenger to a
seat; a first controller for rotating the motor in order to at
least retract the webbing; and a second controller for either
generating a collision danger alarm when a distance between a
vehicle of the passenger and an object ahead becomes less than a
specified value or a dozing alarm by determining an indication of
dozing by the passenger of the vehicle; wherein the first
controller alters a tension of the webbing while the webbing is
fastened, on a basis of a number of times of alarm generation with
regard to at least either the collision danger alarm or the dozing
alarm.
9. A seatbelt device comprising: a retractor using a motor for
retracting and protracting a webbing that secures a passenger to a
seat; a first controller for rotating the motor in order to at
least retract the webbing; and a second controller for either
generating a collision danger alarm when a distance between a
vehicle of the passenger and an object ahead becomes less than a
specified value or a dozing alarm by determining an indication of
dozing by the passenger of the vehicle; wherein the first
controller alters a retraction power of the webbing while the
webbing is fastened, on a basis of a number of alarm generation
times with regard to at least either the collision danger alarm or
the dozing alarm.
10. A seatbelt device comprising: a retractor using a motor for
retracting and protracting a webbing that secures a passenger to a
seat; a first controller for rotating the motor in order to at
least retract the webbing; and a second controller for either
generating a collision danger alarm when a distance between a
vehicle of the passenger and an object ahead becomes less than a
specified value or a dozing alarm by determining an indication of
dozing by the passenger of the vehicle; wherein the first
controller generates an alarm by rotating the motor to alternately
and repeatedly protract and retract the webbing; and wherein the
first controller alters a vibration cycle of the alarm on a basis
of a number of times of alarm generation with regard to at least
either the collision danger alarm or the dozing alarm.
11. A seatbelt device comprising: a retractor using a motor for
retracting and protracting a webbing that secures a passenger to a
seat; and a controller for rotating the motor in order to at least
retract the webbing and for generating an alarm; wherein the
controller executes a control program for setting a threshold value
of alarm generation, and executes a seatbelt-fastened-state
duration program; wherein the controller controls an ease of alarm
generation by altering the threshold value on a basis of a
seatbelt-fastened-state duration determined by the
seatbelt-fastened-state duration program.
12. The seatbelt device according to claim 11, wherein the
seatbelt-fastened-state duration program receives a control signal
from a buckle connection detector for determining a state of
connection between a buckle and a tongue.
13. A seatbelt device comprising: a retractor using a motor for
retracting and protracting a webbing that secures a passenger to a
seat; and a controller for rotating the motor in order to at least
retract the webbing, wherein the controller executes a program for
determining a number of times that the seatbelt device in an
unfastened state turns into a fastened state; and wherein the
controller alters a retraction power of the webbing on a basis of
the number of times a change of state is determined by the
program.
14. The seatbelt device according to claim 13, wherein the program
for determining the number of times that the seatbelt device in the
unfastened state turns into the fastened state, receives a control
signal from a buckle connection detector for determining a state of
connection between a buckle and a tongue.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to a seatbelt device for
securing a passenger to a seat and ensuring the safety of such
passenger, and particularly relates to a seatbelt device comprising
a retractor for retracting and protracting a webbing with a power
source such as a motor.
2. Description of the Related Art
A seatbelt device comprising a retractor for retracting and
protracting a webbing has been conventionally known, for example,
as described in U.S. Pat. No. 4,511,097. This typical seatbelt
device proposes a combination with a motor for protracting and
retracting the webbing.
However, if an emergency situation occurs (disconnection within the
motor, for example) and a drive current cannot be supplied to the
motor of the seatbelt device, no driving force or braking force
will be generated, and it is possible that the motor will slip. In
such case, after the webbing is fastened, the webbing can be
protracted but will not be automatically retracted, and thus, the
slack in the webbing is not removed. Driving a vehicle with a slack
in the webbing is undesirable as the passenger's security cannot be
sufficiently ensured.
The respective controls mentioned above are performed uniformly
without consideration to the different uses of the seatbelt by
various passengers, and are not necessarily optimum for each
passenger. Thus, a typical conventional passenger
security/protection device for vehicles could not, in a sufficient
manner, provide a comfortable seatbelt-wearing environment or
appropriately secure and protect the passenger.
Although a seatbelt is for securing and protecting the passenger
upon a vehicle accident, it is also desired that such seatbelt be
disengaged immediately after the accident so that the passenger may
escape from such vehicle.
Conventionally, when a vehicle accidentally went underwater, the
passenger would remove the webbing from the buckle and open the
door or window to escape from such vehicle. In this case, the
passenger may instantaneously panic, and try to escape without
disengaging his/her seatbelt, and the seatbelt device will
therefore hinder the passenger's escape. When a vehicle
accidentally rolls over, also, the passenger may panic and try to
escape without disengaging the seatbelt.
Upon rescuing a passenger from the rolled over vehicle, it is
difficult to disengage the buckle of the seatbelt device as it is
mounted on the central side of the vehicle interior. Thus, the
webbing is often cut in order to rescue the passenger.
Thereby, for example, proposed in Japanese Patent Laid-Open
Publication No. Sho 59(1984)-40964 is to provide a buckle
disengagement device for automatically disengaging the buckle in
order to let the passenger free. According to this structure, it is
possible to disengage the buckle in emergency situations.
Nevertheless, if the buckle is disengaged due to a misdetection,
the passenger must go through the trouble of reconnecting the
tongue plate, which the webbing passes through, to the buckle.
SUMMARY OF THE INVENTION
The present invention was devised in order to resolve the
aforementioned conventional problems and an object thereof is to
provide a passenger security/protection device for vehicles capable
of realizing a comfortable seatbelt-wearing environment as well as
appropriately securing and protecting a passenger.
Another object of the present invention is to provide a seatbelt
device capable of realizing the immediate escape or rescue of the
passenger after a vehicle accident.
A further object of the present invention is to provide a seatbelt
device capable of realizing extra safety and a swift escape of the
passenger by protracting the seatbelt in accordance with the state
of the vehicle accident.
In order to achieve the aforementioned objects, the present
invention provides a seatbelt device comprising: a retractor which
uses a motor for retracting and protracting a webbing that secures
a passenger to a seat; and a controller for rotating the motor in
order to at least retract the webbing; wherein the controller
changes the protraction mode of the webbing in accordance with the
state of the webbing fastened by the passenger.
The retractor comprises: a reel to which the webbing is wrapped
around; a motor for rotating the reel via a power transmitting
mechanism; a rotation detection element for detecting the rotation
of the reel; a locking mechanism for locking the rotation of the
reel in emergency situations; wherein, when the controller does not
detect the rotation of the reel after supplying drive signals to
the motor, the controller supplies activation signals to the
locking mechanism ordering the activation of the locking
mechanism.
When the webbing cannot be retracted with a motor, this structure
minimizes the possibility of a passenger wearing a loose webbing
(seatbelt) by preventing the protraction of the webbing.
The controller controls the drive of the motor and alters the
protraction mode of the webbing based on at least one condition
among the slack, tension and retraction power of the webbing, and
vibration pattern of the webbing for determining the generation of
an alarm.
The controller comprises an alteration element for altering, in
accordance with the state of webbing fastened by the passenger, at
least one condition among the slack, tension and retraction power
of the webbing, and vibration pattern of the webbing for
determining the generation of an alarm.
According to this structure, since at least one condition among the
slack, tension and retraction power of the webbing, and vibration
pattern of the webbing for determining the generation of an alarm
is altered in accordance with the state of webbing fastened by the
passenger, it is possible to provide a comfortable seatbelt-wearing
environment and to appropriately secure and protect the
passenger.
Moreover, the seatbelt device according to the present invention
may further comprise an adjustment element for adjusting the
contents altered by the alteration element.
Even if the contents altered by the alteration element do not suit
the passenger, this structure enables the adjustment of such
altered contents with the adjustment element. Thus, it is possible
to provide an optimum seatbelt-wearing environment for each
passenger and to appropriately secure and protect the passenger at
all times.
The seatbelt device according to the present invention may further
comprise an accident detection element for detecting the state of
the vehicle accident, wherein the controller alters the protraction
mode of the webbing with a motor in correspondence with the state
of accident.
With this structure, it is possible to secure the passenger to
his/her seat upon removing the slack in the webbing before the
accident, and to loosen the webbing in an appropriate timing in
correspondence with the state of the vehicle after the accident.
Thus, this is preferable as the passenger's safety and ease of
escape are provided.
The locking mechanism may include: a mechanical locking mechanism
for mechanically locking the rotation of the reel; and at least (a)
webbing acceleration sensor for activating the mechanical locking
mechanism in correspondence with a sudden protraction of the
webbing; or (b) a vehicle acceleration sensor for activating the
mechanical locking mechanism upon considerable deceleration.
The webbing acceleration sensor and vehicle acceleration sensor may
respectively comprise an electromagnetic actuator for compulsorily
activating the mechanical locking mechanism in correspondence with
the supply of activation signals.
The controller may be structured so that it does not activate the
electromagnetic actuator when the reel is rotating due to the
passenger protracting the webbing.
With this structure, it is possible to prevent the hindrance of the
protraction of the webbing necessary for fastening the webbing.
The electromagnetic actuator may include: a mechanical urging
element for providing a mechanical urge to the actuator in order to
activate the webbing acceleration sensor or vehicle acceleration
sensor; and an electromagnetic force generating element for
generating electromagnetic force which suppresses the mechanical
urge; wherein the electromagnetic actuator maintains the
electromagnetic force in a stationary state.
Even if the power source to the motor or seatbelt device is cut off
due to some problem, this structure activates the mechanical
locking mechanism of the reel (i.e., webbing) with the mechanical
urging element upon the termination of the electromagnetic force.
Thereby, the locking of the webbing is secured even if
irregularities occur to the electrical system.
The rotation detection element may be structured from a potential
meter connected to the reel.
With this structure, it is possible to learn the rotation quantity
from the standard position and estimate the protraction quantity,
retraction quantity, rotation quantity of the reel (reel shaft),
etc.
The controller is also capable of protracting the seatbelt with the
motor after a predetermined time elapses from the detection of the
accident.
The accident detection element comprises a drowning detection
element for detecting that the vehicle has drowned, and the
controller is capable of rotating the motor in the protracting
direction in correspondence with the detection of this
drowning.
The detection element comprises a rollover detection element for
detecting that the vehicle has rolled over, and the controller is
capable of rotating the motor in the protracting direction in
correspondence with the detection of this rollover after a
predetermined time elapses.
The predetermined time may be set to a time required for the
abatement of the impact incurred to the rolled over vehicle.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagram explaining the structure of the seatbelt device
according to the first embodiment of the present invention;
FIG. 2 is a diagram explaining the structure of the retractor
according to the first embodiment;
FIG. 3 is a functional block diagram explaining the structure of
the controller according to the first embodiment;
FIG. 4 is a diagram explaining the potential meter according to the
first embodiment;
FIG. 5 is a circuit diagram showing a structural example of the
drive circuit of the motor according to the first embodiment;
FIG. 6 is a flowchart explaining the operation of the controller
according to the first embodiment;
FIG. 7 is a perspective view showing an example of one portion of
the webbing retractor according to the first embodiment;
FIG. 8 is a perspective view showing an example of the other
portions of the webbing retractor according to the first
embodiment;
FIG. 9 is a sectional view in the rotational axial direction of the
ratchet wheel of the locking mechanism shown in FIG. 13;
FIG. 10 is a diagram explaining the activation of the locking
mechanism caused by a rapid protraction of the webbing (webbing
acceleration) according to the first embodiment;
FIG. 11 is a diagram explaining the lock arm according to the first
embodiment;
FIG. 12 is a diagram explaining the inertia plate according to the
first embodiment;
FIG. 13 is a diagram explaining the activation of the locking
mechanism caused by the webbing acceleration according to the first
embodiment;
FIG. 14 is a diagram explaining the activation of the locking
mechanism caused by the webbing acceleration according to the first
embodiment;
FIG. 15 is a diagram explaining the activation of the locking
mechanism caused by the webbing acceleration according to the first
embodiment;
FIG. 16 is a diagram explaining the operation of the
electromagnetic actuator (unlocked state) according to the first
embodiment;
FIG. 17 is a diagram explaining the operation of the
electromagnetic actuator (locked state) according to the first
embodiment;
FIG. 18 is a diagram explaining an example of another
electromagnetic actuator;
FIG. 19 is a diagram explaining the retractor according to the
second embodiment of the present invention;
FIG. 20 is a block diagram explaining the structure of the
controller according to the second embodiment;
FIG. 21 is a flowchart explaining the belt-retraction processing of
the CPU in response to a collision prediction according to the
second embodiment;
FIG. 22 is a flowchart explaining the belt-protraction processing
of the CPU in response to the drowning of a vehicle according to
the second embodiment;
FIG. 23 is a flowchart explaining the belt-protraction processing
of the CPU in response to the rollover of a vehicle according to
the second embodiment;
FIG. 24 is a diagram explaining an example of the unlocking
mechanism (lock activated state) according to the second
embodiment;
FIG. 25 is a diagram explaining an example of the unlocking
mechanism (unlocked state) according to the second embodiment;
FIG. 26 is a sectional view explaining the inactive state of the
pole actuator according to the second embodiment;
FIG. 27 is a sectional view explaining the active state of the pole
actuator according to the second embodiment;
FIG. 28 is a diagram explaining the retractor according to the
third embodiment of the present invention;
FIG. 29 is a circuit diagram of the motor drive circuit according
to the third embodiment;
FIG. 30 is a diagram showing an example of a control program
executed by the controller according to the third embodiment;
and
FIG. 31 is a diagram explaining the retractor according to the
fourth embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
(First Embodiment)
The seatbelt device according to the first embodiment of the
present invention is explained with reference to the relevant
drawings.
FIG. 1 shows the seatbelt device of the first embodiment. The
seatbelt device is structured of an electromotive retractor 100A
for retracting a webbing 302 which secures the passenger to a seat
301, a through-anchor 303 for folding back the webbing near the
passenger's shoulder, a tongue plate 305 to which the webbing
passes through and which engages with a buckle 304 arranged at the
passenger's abdominal region, an anchor 306 for securing one end of
the webbing 302 to the vehicle, a switch 307 built inside the
buckle, a controller 200A (explained later, refer to FIG. 2),
etc.
FIG. 2 is a diagram explaining the outline of the structure of the
retractor 100A. In FIG. 2, the retractor 100A comprises a frame
101. Rotatably provided to this frame 101 are a reel 103 for
winding the webbing 302 (refer to FIG. 1) and a reel shaft 103a
which is connected to the reel 103 and is the central axis of the
reel rotation.
Secured to the right end of the reel shaft 103a is a seatbelt
locking mechanism 102 for locking the webbing when a prescribed
deceleration works on a vehicle or when the webbing 302 is
protracted at a prescribed acceleration. Further provided to the
locking mechanism 102 is an electromagnetic actuator 112 explained
later for compulsorily activating such locking mechanism 102. The
activation of the electromagnetic actuator 112 is controlled by the
output of the controller 200A explained later.
Provided to the left end of the reel shaft 103a are a pretensioner
104, pulley 105, and potential meter 111. The pretensioner 104
activates pursuant to the output of the collision detector not
shown, rotates the reel shaft 103a in the retracting direction of
the webbing 302, and secures the passenger to the seat by
compulsorily retracting the webbing 302. The pretensioner 104 may
be, for example, a powder pretensioner, and is structured of a gas
generator, a cylinder for sealing the gas generated by this gas
generator, a piston which moves within this cylinder by gas
pressure, a timing belt (as a power transmitting mechanism) for
converting this piston movement into a rotary motion of the reel
shaft 103a via the clutch mechanism, etc.
The pulley 105 secured to the reel shaft 103a is connected to a
pulley 106 secured to the axis of the direct current (DC) motor 110
via the timing belt 107. A prescribed number of outer gear teeth
are formed respectively on the outer periphery of the pulleys 105,
106, and a prescribed number of inner gear teeth are formed on the
inner periphery of the belt 107. The respective gear teeth of the
pulley 105 of the reel shaft 103a, the pulley 106 of the motor, and
the timing belt 107 are engaged with each other in proper
quantities, and the rotation of the motor 110 is transmitted to the
reel shaft 103a. The motor 110 is secured to the frame 101 in at
least two points, and is driven by the output of the controller
200A.
The potential meter 111 provided on the left end of the reel shaft
103a is, as shown in FIG. 4, structured of a resistor for applying
voltage to both ends thereof, and a slider which interlocks with
the rotation of the reel shaft 103a. This potential meter 111
outputs to the controller 200A a voltage value corresponding to the
rotation quantity from the standard position of the reel shaft
103a.
FIG. 3 is a functional block diagram explaining the structural
outline of the controller 200A. As shown in FIG. 3, the controller
200A is structured of a microcomputer system. The CPU 201 loads
control programs and data retained in the ROM 202 to the work area
of the RAM 203, and controls the operation of the DC motor 110 and
the solenoid as the electromagnetic actuator 112. The output
voltage of the aforementioned potential meter 111 is A/D converted
in prescribed cycles by the input interface 204.
The input interface 204 has a CPU built therein, and monitors the
converted output voltage data. For example, with the difference
between the present and previous output voltage data, it judges the
rotational state of the reel shaft 103a and sets a "shaft rotating"
flag to the flag area of the RAM 203. With the difference between
the present and previous output voltage value being positive or
negative, the input interface 204 further sets a "protraction" flag
or a "retraction" flag of the webbing 302 to the flag area of the
RAM 203. Moreover, it writes the output voltage data to the
rotation quantity area of the RAM 203 with DMA operation. The input
interface 204 sets an engagement/disengagement flag of the seatbelt
device to the flag area of the RAM 203 upon receiving the
open/close output of the buckle switch 307 which is built in the
buckle of the seatbelt device and which generates an output in
correspondence to the engagement/disengagement of the seatbelt
device.
When prescribed conditions set to the control program are
fulfilled, the CPU 201 provides to the output interface 205 a
normal rotation order, reverse rotation order, or drive suspension
order for the DC motor 110.
The output interface 205 generates gate signals G1, G2 in
correspondence to these orders and supplies such signals to the
motor drive circuit 206. G1 and G2 are set as "H" and "L" in
response to a normal rotation order, as "L" and "H" in response to
a reverse rotation order, and as "L" and "L" in response to a drive
suspension order, respectively.
FIG. 5 is circuit diagram showing the structural example of the
motor drive circuit 206. A transistor bridge circuit is structured
of four transistors, namely, PNP transistors Q1 and Q2, and NPN
transistors Q3 and Q4. Emitters of transistors Q1 and Q2 are
connected, and a power source Vc is supplied to this connection
point. Emitters of transistors Q3 and Q4 are also connected, and a
ground is supplied to this connection point. The collector of
transistor Q1 and the collector of transistor Q3 are connected via
diode D1. The collector of transistor Q2 and the collector of
transistor Q4 are connected via diode D2. The base of transistor Q1
and the collector of transistor Q4 are connected via the urge
resistance R1. The base of transistor Q2 and the collector of
transistor Q3 are connected via the urge resistance R2. A DC motor
M is connected mutually between the respective collectors of
transistors Q1 and Q2.
In the aforementioned structure, when a normal rotation order
signal (G1="H", G2="L") is supplied to the respective gates of
transistors Q3 and Q4 from the output interface 205, transistor Q3
becomes conductive and transistor Q4 becomes non-conductive. The
collector of transistor Q3 becomes a ground level by conductivity,
urges the base of transistor Q2 to a low level (approximate ground
level) via resistance R2, and makes transistor Q2 conductive. The
collector of transistor Q4 becomes an approximate power source Vc
level, urges the base of transistor Q2 to a high level via
resistance R1, and makes transistor Q1 non-conductive. As a result
thereof, a current path is formed in the orderly direction of the
ground path of power source Vc, transistor Q2, motor M, diode D1,
and transistor Q3, and the motor M rotates in the direction for
retracting the webbing.
When a reverse rotation order signal (G1="L", G2="H") is supplied
to the respective gates of transistors Q3 and Q4 from the output
interface 205, transistor Q3 becomes non-conductive and transistor
Q4 becomes conductive. The collector of transistor Q4 becomes a
ground level, urges the base of transistor Q1 to a low level via
resistance R1, and makes transistor Q1 conductive. The collector of
transistor Q3 becomes an approximate power source Vc level, urges
the base of transistor Q2 to a high level via resistance R2, and
makes transistor Q2 non-conductive. As a result thereof, a current
path is formed in the orderly reverse direction of the ground path
of power source Vc, transistor Q1, motor M, diode D2, and
transistor Q3, and the motor M rotates in the direction for
protracting the webbing.
When a drive suspension order signal (G1="L", G2="L") is supplied
to the respective gates of transistors Q3 and Q4 from the output
interface 205, the NPN-type transistors Q3 and Q4 both become
non-conductive. When transistor Q3 becomes non-conductive from a
conductive state, the collector of transistor Q3 rises from a
ground level to an approximate power source level, urges the base
of transistor Q2 to a high potential, and interrupts transistor Q2
as well. Similarly, when transistor Q4 becomes non-conductive from
a conductive state, the collector of transistor Q4 rises from a
ground level to an approximate power source level, urges the base
of transistor Q1 to a high potential, and interrupts transistor Q1
as well. Accordingly, when a drive suspension order is given, the
respective transistors structuring the bridge become
non-conductive.
Referring back to FIG. 3, the CPU 201 provides to the output
interface 205 an activation order of the solenoid as the actuator
112 when prescribed conditions for preventing the slack in the
webbing 302 are fulfilled. The activation order set to the register
flag of the output interface 205 is amplified by a power amplifier
207 from a logical level signal to a level capable of activating
the solenoid, and then provided to such solenoid. By the operation
of this solenoid, the actuator moves, and the locking mechanism
explained later of the retractor 100A is activated.
FIG. 6 is a flowchart explaining the operation of the CPU 201 of
the controller 200A.
By fulfilling the conditions such as the on state (buckle switch
307 in the closed state) of the seatbelt device fastening flag, the
CPU 201 judges in prescribed intervals that the locking of the
protraction of the webbing is under a permissible condition, and
performs the subroutine (S20).
In a state wherein the DC motor 110 is not driven, the CPU 201
foremost judges the on/off of the "webbing protraction" flag of the
flag register (flag area) of the RAM 203. When the "webbing
protraction" flag is "on" (S22; YES), the CPU 201 ends the routine
without activating the locking mechanism as the webbing is being
protracted by the passenger, and returns to the main program (S36).
When the protraction of the webbing is not being conducted (S22;
NO), the CPU 201 provides a reverse rotation order for the motor to
the output interface 205 (S24). The output interface 205 provides a
gate signal to the motor drive circuit 206 and, when the DC motor
110 rotates in the protracting direction, the potential meter 111
also rotates in the protracting direction. A protraction flag is
set to the flag register by the input interface 204 which monitors
the change in the output voltage of the potential meter 111. The
CPU 201 confirms (judges) the above (S26). When no protraction flag
is set (S26; NO), in other words when the potential meter 111 is
not rotating toward the protraction side, a malfunction of the DC
motor 110, retractor, and so on may be considered. The CPU 201
activates the solenoid via the output interface 205, prevents the
protraction of the webbing 302 by activating the locking mechanism,
and prevents the increase of slack in the webbing 302. The CPU 201
then sets a malfunction detection flag to the flag register (S28),
suspends the rotation order for the motor 110 (S34), and returns to
the main program (S36).
When the protraction flag is set to on (S26; YES), the CPU 201
judges the operation of the protracting direction of the webbing
302 as normal since the potential meter 111 is rotating in
correspondence with the rotation order of the DC motor 110. Next,
the CPU 201 orders the normal rotation of the motor 110 to the
output interface 205. The output interface 205 provides a gate
signal to the motor drive circuit 206 (S30).
When the DC motor 110 rotates in the retracting direction, the
potential meter 111 also rotates in the retracting direction. A
retraction flag is set to the flag register by the input interface
204 which monitors the change of output voltage of the potential
meter 111. Thereby, it is recognized that the webbing 302 has been
retracted in correspondence with a normal rotation order of the DC
motor 110 (S32; YES). As the operation is normal, the CPU 201
orders the output interface 205 to suspend the DC motor 110, and
the DC motor 110 is thereby suspended (S34). The CPU 201 returns to
the main program thereafter (S36).
When the DC motor 110 does not rotate in the retracting direction
or if there is some irregularity, the potential meter 111 will not
rotate in the retracting direction. The input interface 204 does
not set a retraction flag to the flag register as the output
voltage of the potential meter 111 does not show a prescribed
change. When the CPU 201 judges this, it is determined to be an
error (S32; NO). When the DC motor 110 does not activate, the reel
shaft 103a may slip and, in order to prevent this, the protraction
locking mechanism of the webbing 302 is activated. The CPU 201
operates the solenoid via the output interface 205, prevents the
protraction of the webbing 302 by activating the locking mechanism
of the webbing 302, and prevents the increase of slack in the
webbing 302. The CPU 201 then sets the malfunction detection flag
to the flag register (S28), suspends the rotation order of the
motor 110 (S34), and returns to the main program (S36).
Like this, when a malfunction occurs in the retractor 100A, it is
possible to prevent the slack in the webbing by preventing the reel
103 from slipping.
FIGS. 7 through 18 are exploded perspective views and vertical
section views of principle portions explaining mainly the seatbelt
locking mechanism (reel mechanical locking mechanism, webbing
acceleration sensor, vehicle deceleration sensor) and the
electromagnetic actuator 112 of the retractor 100A. Incidentally, a
pretensioner is not mounted in the drawing shown in FIG. 7. When
necessary due to a special character of the vehicle, as shown in
FIG. 2, the pretensioner may be arranged between the retractor base
1 and the timing belt 15 shown in FIG. 7.
Referring to FIGS. 7 through 12, the retractor base 1 has an
approximate C-shaped cross section, the opposing side plates 1a, 1b
respectively have provided thereto opposing winding shaft through
holes, and the reel 3, which is the winding shaft, for retracting
the webbing 302 (refer to FIG. 1) passes through the winding shaft
through holes and is rotatably provided thereto by the winding
shaft.
Inner gear teeth 2 are formed on the inner periphery of the winding
shaft through holes provided to the side plate 1a, and a ring 4 is
juxtaposed on the exterior of the winding shaft through holes.
Drawing is performed on the inner periphery of the ring 4 and, when
the ring 4 is secured to the exterior face of the side plate 1a by
a rivet 40, a gap in the axial direction between the inner gear
teeth 2 and the inner peripheral edge of the ring 4 is formed.
Further, arranged on the side plate 1a of the base 1 is an
emergency locking mechanism for preventing the protraction of the
webbing 302 during emergency situations. Arranged on the side plate
1b of the base 1 are a pulley 105 connected to the axis 15c
(corresponds to reel shaft 103a) driven by the DC motor 110 via the
timing belt 107, and a timing belt unit 15 including a potential
meter 111 and the like. The reel 3 is a winding shaft having an
approximate cylindrical shape and formed integrally with aluminum
alloy and the like. A slit opening 28a in the diameter direction
for passing the webbing end through and retaining such webbing end
is provided to the barrel 28 to which the webbing 302 is wound. A
separately formed flange 13 is mounted on the outer periphery of
the reel 3, and prevents the winding disorder of the webbing. The
position of entrance and exit of the webbing 302 wound on the outer
periphery of the reel 3 mounted on the retractor base 1 is
restricted by such webbing being passed through the webbing guide
41 mounted on the upper part of the back side of the retractor base
1.
Although a rotation spindle for rotatably supporting the reel 3 is
protrusively provided to both ends of the reel 3, a separately
formed spindle pin 6 is press fitted to the sensor side end face of
the reel 3 as the rotation spindle. Moreover, protrusively provided
to the sensor side end face of the reel 3 is a spindle 7 for
rotatably supporting a pole 16, which is a locking member, in a
rocking manner, capable of being engaged with the inner gear teeth
2 formed on the side plate 1a. Provided to the sensor side end face
of the reel 3 is a pressure face 45 which determines the position
of the pole back end portion 16e opposite to the rocking side end
of the pole 16 when the pole 16 rockingly rotates in the engagement
direction with the inner gear teeth 2 and, when a large load is
inflicted upon the pole 16 between the inner gear teeth, receives
such load.
On the sensor side end face of the reel 3, provided is a stopper
protrusion 8 for restricting the counterclockwise rotation of the
rocking lever 20 supported in a rocking manner by the ratchet wheel
18, which is the latch member of the lock activation element
explained later. The convex portion 9 is a recess element for
preventing a pull coil spring 36 which rotationally urges the
ratchet wheel 18 in the webbing protracting direction (direction of
arrow X2 in FIG. 8) and the arm 26c of the lock arm 26 which
presses the sensor spring 25 explained later, from interfering with
the reel 3.
To the rocking end of the pole 16, formed integrally are gear teeth
16c capable of engaging with and in correspondence to the inner
gear teeth 2 structured on the side plate 1a. A shaft hole 16a to
which the spindle 7 loosely engages is provided at the central
portion of the pole 16. Provided to the sensor side face of the
pole 16 are an engagement protrusion 16b positioned at the rocking
end side and a pressure protrusion 16d positioned at the pole rear
end portion 16e.
That is to say, as the spindle 7 is loosely engaged with the shaft
hole 16a, the spindle 7 supports the pole 16 in a rockingly
rotatable manner and enables a prescribed relative displacement.
The tip of the spindle 7 passing through the shaft hole 16a of the
pole is caulked to a stopper hole 17b of the retaining plate 17,
which is engaged with a spindle pin 6 pressed into the reel 3 by
such pin passing through the perforation hole 17a. Thus, the
retaining plate 17 prevents the pole 16 from rising from the end
face of the reel 3.
The end of the engagement protrusion 16b of the pole 16 is inserted
into a cam hole 18a formed on the ratchet wheel 18, which is
arranged on the exterior of the retaining plate 17 and rotatably
supported by spindle pin 6. Thus, when the ratchet wheel 18
relatively rotates toward the webbing retracting direction
(direction of arrow X1 in FIG. 8) in relation to the reel 3, the
cam hole 18a works to move the tip of the engagement protrusion 16b
outward toward the radius direction from the rotational central
axis of the reel 3. Thereby, the pole 16 rockingly rotates around
the spindle 7 in the engagement direction (direction of arrow Yl in
FIG. 7) with the inner gear teeth 2 structured on the side plate
1a.
In other words, by the pole 16 rockingly rotating toward the
engagement direction with the inner gear teeth 2 and the engagement
teeth 16c of the pole 16 engaging with the inner gear teeth 2,
structured is the locking element for preventing the rotation of
the reel 3 in the protracting direction of the webbing. The ratchet
wheel 18 is a ratchet with its central hole rotatably supported by
the spindle pin 6, and ratchet teeth 18b for engaging with the
sensor arm 53 of the vehicle acceleration sensor 51 are formed on
the outer periphery thereof. The flange 6a of the spindle pin 6
supports the central hole 30a of the inertia plate 30, which is a
discoid inertial member for structuring the webbing acceleration
sensor, which is an inertia sensor for sensing the acceleration of
the protraction of the webbing 302. The stopper pawl 23
protrusively provided toward the exterior of the retractor at the
peripheral edge of the central hole of the ratchet wheel 18
determines the position of the thrust direction of the inertia
plate 30 by engaging with the engagement hole 30b. An engagement
protrusion 31 of the inertia plate 30 is engaged with the long hole
24 formed in the ratchet wheel 18. One edge 24a of the long hole 24
determines the position of the rotating direction of the inertia
plate 30 upon the inactivation of the emergency locking mechanism
(refer to FIG. 10).
As shown in FIG. 10, a shaft 22 for rotatably supporting the lock
arm 26 and a spring hook 55 are protrusively provided on the
exterior face of the ratchet wheel 18. And as shown in FIG. 12, an
opening 56 for inserting the spring hook 55 is provided to the
inertia plate 30. This opening 56 is formed in a shape of a long
hole such that the inertia plate 30 is able to relatively rotate in
relation to the ratchet wheel 18 while the spring hook 55 is
inserted therein. On the other end thereof, provided is a spring
hook 57 in correspondence with the spring hook 55.
A compression coil spring 58 is engaged and inserted between this
pair of spring hooks 55, 57. As shown in FIG. 13, this compression
coil spring 58 is urged such that the engagement protrusion 31 on
the inertia plate 30 maintains contact (i.e., unlocked state) with
the other end 24b of the long hole 24 formed in the ratchet wheel
18.
A spring hook 21 for hooking one end of the extension coil spring
36, wherein the other end thereof is hooked to the hook 17c of the
retaining plate 17, is provided to the inner face of the ratchet
wheel 18. The extension coil spring 36 rotationally urges the
ratchet wheel 18 in the webbing protracting direction (direction of
arrow X2) in relation to the reel 3. As shown in FIG. 11, the lock
arm 26 is provided with an engagement pawl 26b for engaging with
the inner gear teeth 34a of the gear case 34, and an arm 26c for
pressing the longitudinal central portion of the linear sensor
spring 25, wherein both ends thereof are supported by a pair of
hooks 18d provided on the exterior face of the ratchet wheel
18.
The lock arm 26 thereby structures a stopper member for preventing
the rotation of the ratchet wheel 18 in the webbing protracting
direction by the engagement pawl 26b engaging with the inner gear
teeth 34a, which are engaging members. The engagement pawl 26b is
pressure urged toward the contact portion 32 of the inertia plate
30 due to the urging force of the sensor spring 25. Incidentally,
an opening is formed in the ratchet wheel 18 corresponding to the
rocking range of the arm 26c, and the arm 26c passes through such
opening. This is in order to guarantee the state of engagement of
the arm 26c with the sensor spring 25.
The contact portion 32 is structured as a cam face to which the
engagement pawl 26b of the lock arm 26 slidably contacts,
comprising a first cam face 32a wherein the inertia plate 30 does
not influence the lock arm 26, and a second cam face 32b which
reciprocates the lock arm 26 such that the engaging pawl 26b
engages with the inner gear teeth 34a in accordance with the
rotation delay of the inertia plate 30 in relation to the reel
3.
In the unlocked state of the emergency locking mechanism, the first
cam face 32a is in contact with the back portion 26d of the lock
arm 26 and, until the rotation delay of the inertia plate 30 in
relation to the reel 3 exceeds a prescribed value, the back portion
26d will not come in contact with the second cam face 32b. The
length of the first cam face 32a (i.e., rotation quantity of the
inertia plate 30 in a state where the back portion 26d is slidably
in contact with the first cam face 32a) is set. such that, even if
the rotation delay of the inertia plate 30 in relation to the reel
3 occurs due to the inertial force working on the inertia plate 30
when the webbing 302 is completely retracted, the back portion 26d
of the lock arm 26 will not reach the second cam face 32b with such
level of rotation delay.
Regarding the lock arm 26 of the first embodiment, a contact pawl
26e is formed on the rocking end on the side opposite to the
engagement pawl 26b. In correspondence with this contact pawl 26e,
a step 33 capable of coming in contact with the contact pawl 26e is
provided to the inertia plate 30. The step 33 restricts the
movement in the locking direction of the lock arm 26 by coming in
contact with the contact pawl 26e when the inertia plate 30 is in
an unlocked state and in its initial position. As shown in FIGS. 14
and 15, when a rotation delay exceeding a prescribed value occurs
to the inertia plate 30 and the back portion 26d of the lock arm 26
comes in contact with the second cam face 32b, the lock arm 26 is
able to reciprocate in the locking direction due to the pressure
effect of the second cam face 32b.
A rocking lever 20, which is supported by the shaft hole 20a, is
rockingly provided to the spindle 19 protrusively formed on the
inner face of the ratchet wheel 18. The rocking lever 20 is
assembled between the reel 3 and the ratchet wheel 18 such that the
rotation thereof in the counterclockwise direction is adequately
restricted by the stopper protrusion 8 protrusively formed on the
sensor side end face of the reel 3, and the rotation thereof in the
clockwise direction is adequately restricted by the pressure
protrusion 16d protrusively formed on the sensor side face of the
pole 16 coming in contact between the spindle 19 and the stopper
protrusion 8.
Provided to the central portion of the gear case 34 arranged on the
exterior of the inertia plate 30 is a shaft supporter 34b for
rotatably supporting the reel 3 via the spindle 6. A collar 6a of
the spindle 6 is in contact with the bottom face of the axis
supporter 34b, and is the face for determining the position of the
axial direction of the reel 3. Provided to the lower part of the
gear case 34 is a housing 50 in a shape of a box for housing the
vehicle acceleration sensor 51, which is an inertia sensing
element, for sensing the acceleration of the vehicle. A sensor
cover 35 is provided on the exterior of the side plate 1a covering
the gear case 34.
The activation of the seatbelt device retractor according to the
first embodiment is now explained.
In an ordinary state of use, as shown in FIG. 13, the ratchet wheel
18 is urged in the webbing protracting direction (direction of
arrow X2 in FIG. 13) in relation to the reel 3 due to the urging
force of the pull coil spring 36 hooked on spring hook 21 and the
hook 17c of the plate 17. Thus, the pole 16, wherein the engagement
protrusion 16b thereof engages with the cam hole 18a, is urged in a
disengagement direction with the inner gear teeth 2. Thus, the reel
is rotatable and the webbing is protractable.
When the webbing acceleration sensor inclusive of the inertia plate
30 or the vehicle acceleration sensor 51 is activated in emergency
situations such as upon a collision, the lock arm 26 or the sensor
arm 53, which are stopper elements for preventing the rotation of
the locking activation element in the webbing protracting
direction, prevents the rotation of the ratchet wheel 18 in the
webbing protracting direction and activates the retractor locking
element.
When the vehicle acceleration sensor 51 or the webbing acceleration
sensor is activated and the webbing 302 is protracted from the
retractor 100A after the rotation of the ratchet wheel 18 has been
prevented in the webbing protracting direction, the ratchet wheel
18 generates a rotation delay in relation to the reel 3, and
relatively rotates in the webbing retracting direction (direction
of arrow X1). Thus, the cam hole 18a of the ratchet wheel 18 moves
the engagement protrusion 16b of the pole 16 from the rotational
central axis of the reel 3 outward toward the radius direction. The
pole 16 thereby rockingly rotates around the spindle 7 in the
engagement direction (direction of arrow Y1 in FIG. 7) with the
inner gear teeth 2.
When the webbing 302 is further protracted from the retractor 100A,
the engagement teeth 16c of the pole 16 engage with the inner gear
teeth 2, and such engagement is completed. In this state, there is
a gap between the pole rear end portion 16e of the pole 16 and the
pressure receiving face 45 of the reel 3, and the rotation of the
rocking lever 20 is restricted to be substantially without any
looseness by the stopper protrusion 8 of the reel 3 and the
pressure protrusion 16d of the pole 16.
Here, the shaft hole 16a of the pole 16 is loosely engaged with the
spindle 7 of the reel 3, and as it is further supported in relation
to the reel 3 in a rockingly rotatable manner and enabling a
prescribed relative displacement, when the webbing 302 is further
protracted from the retractor 100A, the pole 16 relatively rotates
around the rotational central axis of the reel 3 until the pole
rear end portion 16e comes in contact with the pressure receiving
face 45.
Although the pressure protrusion 16d of the pole 16 is in an
immovable position relationship with respect to the side plate 1a,
the stopper protrusion 8 of the reel 3 rotates in the webbing
protracting direction (direction of arrow X2). By this movement,
the rocking lever 20 is rockingly rotated in the clockwise
direction shown in FIG. 8 as the rocking end is pressed by the
stopper protrusion 8 with the contact point with the pressure
protrusion being the rotational fulcrum. When the rocking lever 20
rockingly rotates in the clockwise direction shown in FIG. 8 with
the contact point with the pressure protrusion being the rotational
fulcrum, the shaft hole 20a supported by the spindle 19 of the
ratchet wheel rotates in the webbing retracting direction
(direction of arrow X1) in relation to the rotational central axis
of the reel 3. As a result thereof, the ratchet wheel 18 rotates in
reverse in the webbing retracting direction in relation to the reel
3.
Therefore, even if the vehicle acceleration sensor 51 or webbing
acceleration sensor is activated and the locking element of the
retractor 100A is in a locked state and preventing the reel 3 from
rotating in the webbing protracting direction, the ratchet wheel
18, which the rotation in the webbing protracting direction is
prevented, is capable of disengaging the sensor arm 53 of the
vehicle acceleration sensor 51 or the lock arm 26 of the webbing
acceleration sensor from the engagement with the inner gear teeth
of the gear case 34.
When further tension works on the webbing 302 when the pole 16 is
in a locked state, the portion supporting the axis supporter 34b of
the gear case 34 and the axis 15c of the timing belt 15 transforms,
and the reel 3 tries to move upward. This movement is prevented by
the contact face 3a and groove 3b formed on the reel 3 respectively
coming in contact with the inner gear teeth 2 and the engagement
teeth 62 on the side plate 1b (c.f. FIG. 7), and such faces receive
the tension working on the webbing 302.
When the vehicle comes to a halt and the tension working on the
webbing 302 is relieved, as the engagement with the ratchet wheel
18 and the sensor arm 53 or the inner teeth gear 34a of the gear
case 34 of the lock arm 26 is already disengaged, the ratchet wheel
18 rotates in the arrow X2 direction in relation to the reel 3 due
to the urging force of the pull coil spring 36 and the cam hole 18a
of the ratchet wheel 18 moves the engagement protrusion 16b of the
pole 16 toward the rotational central axis side of the reel 3.
Here, the tension working on the protracting direction of the
webbing 302 is relieved, and, as the reel 3 is able to rotate in
the webbing retracting direction (direction of arrow X1), when the
reel 3 rotates in the direction of arrow X1 until the tip of the
engagement teeth 16c of the pole 16 does not interfere with the tip
of the inner gear teeth 2, the pole 16 rockingly rotates around the
spindle 7 in the direction to disengage the engagement with the
inner gear teeth 2, and the webbing becomes freely protractable as
the reel 3 is unlocked.
Next, when the DC motor 110 retracts the webbing from its
protracted state and when the webbing 302 is rapidly and completely
retracted in accordance with the rotational power of the timing
belt 15, as the inertia plate 30, which is the inertial member of
the webbing acceleration sensor, keeps on rotating in the
retracting direction in relation to the reel 3 which suddenly
stopped rotating, the inertia plate 30 continues rotating in the
retracting direction in relation to the reel 3 and a rotational
delay arises with regard to the reel 3 in terms of the protracting
direction of the reel 3. Nevertheless, the contact portion 32 of
the inertia plate 30 for reciprocating the engagement pawl 26b of
the lock arm 26 in the engagement direction with the inner teeth
gear 34a of the gear case 34 is structured of two cam faces 32a,
32b for reciprocating the engagement pawl 26b toward the inner
teeth gear 34a after the rotational delay in relation to the reel 3
of the inertial plate 30 has reached a prescribed value. Thus,
until the rotational delay of the inertia plate 30 with regard to
the reel 3 reaches a prescribed value, the engagement pawl 26b will
not reciprocate in the engagement direction with the inner teeth
gear 34.
The present invention according to this embodiment is structured as
above, and an electromagnetic actuator 112 is further provided to
the activating locking mechanism as shown in the lower part of FIG.
8. The electromagnetic actuator 112, as shown in FIGS. 16 and 17,
is structured of a solenoid (excitation coil) 112a, coil spring
(elastic member) 112b, plunger with a collar (magnetic core) 112c,
and arranged at the lower part of the vehicle acceleration sensor
51.
In a normal state, the solenoid 112a is excited. In such state, as
shown in FIG. 16, the plunger 112c does not contact the ball weight
54, and does not influence the locking mechanism 102. When the
controller 200 releases the excitation of the solenoid 112a in
order to lock the webbing (S28), the plunger 112c is raised due to
the urging force of the spring 112b. The tip of the plunger 112c
passes through the opening at the bottom face of the sensor cover
52 and thrusts the ball weight 54. When the ball weight 54 is
pushed up, the sensor arm 53 moves in the upper direction in FIG.
16, and the stopper protrusion 53a engages with the ratchet teeth
18b of the ratchet wheel 18. Thereby, the rotation of the ratchet
wheel 18 in the webbing protracting direction (direction of arrow
X2 in FIG. 8) is prevented. When the webbing is protracted and the
reel 3 rotates in the protracting direction, the rotational
difference in the stopped ratchet wheel and the reel 3 moves the
pole 16 outward toward the radius direction of the reel 3, and
engages with the inner gear teeth 2 of the frame 1a. The rotation
in the protracting direction of the reel 3 is thus prevented.
In this example, when the locking operation is not conducted and
the excitation current is cut off while supplying an excitation
current to the solenoid 112a, the locking operation is endeavored.
That is, the locking mechanism 102 is activated by low-level
activation signals being supplied thereto. Therefore, even if power
to the seatbelt device is cut off, the webbing 302 can be
locked.
FIG. 18 shows another structural example of the electromagnetic
actuator. In this example, the electromagnetic actuator 112 is
structured of a solenoid 112a, plunger 112c, approximate L-shaped
lever 112d wherein one end thereof is engaged with the plunger 112c
and the central portion thereof is rotatably supported, and a coil
spring 112b for applying urging force to the lever 112d in the
clockwise direction in FIG. 18. When the pawl of the lever 112d
moves and comes in contact with the teeth face 18b of the ratchet
wheel 18, the rotation of the ratchet wheel 18 is prevented and the
locking mechanism by the pole 16 and inner gear teeth 2 of the
frame is activated.
In the normal state where an excitation current is being supplied
from the controller 200A to the solenoid 112a, the solenoid 112a
draws the plunger 112c near in resistance to the coil spring 112b,
and the pawl on one end of the lever 112d rotatably supported at
the other end with the plunger 112c is separated from the ratchet
wheel 18. Therefore, the locking mechanism is not activated.
Next, when the CPU detects a malfunction (S26, S32), the supply of
the excitation current from the controller 200A is cut off in order
to lock the webbing (S28). The plunger 112c is protracted in the
downward direction of FIG. 18 by the urging force of the coil
spring 112b, and the lever 112d rotates. Thereby, the pawl of one
end of the lever 112d engages with the teeth 18b of the ratchet
wheel 18 and prevents the rotation of the ratchet wheel 18 in the
webbing protracting direction. When the webbing 302 is protracted
and the reel 3 rotates in the protracting direction, the pole 16
moves outward toward the radius direction due to the rotational
difference between the stopped ratchet wheel 18 and the reel 3, and
engages with the inner gear teeth 2 of the frame 1a. Thereby, the
rotation of the reel 3 in the protracting direction is prevented,
and the lock is completed.
According to the present invention of this embodiment, when a
malfunction in the motor or retraction/protraction is detected, it
is possible to reliably secure the passenger as the protraction of
the webbing is prevented due to the activation of the locking
mechanism. Further, it is preferable in that the locking of the
webbing is secured by the mechanical locking mechanism even if the
power etc. to the motor is cut off.
In the first embodiment, described was an emergency locking
mechanism of the type comprising a webbing acceleration sensor as
well as a vehicle acceleration sensor, but needless to say, the
seatbelt device of the present invention may be a retractor
comprising only the webbing acceleration sensor, or only the
vehicle acceleration sensor.
According to the seatbelt device of the first embodiment, when a
malfunction in the webbing retraction/protraction by the DC motor
is detected, the protraction of the webbing is locked. Thus, it is
possible to reduce, as much as possible, the slack in the webbing
upon a vehicle accident.
(Second Embodiment)
The seat belt device of the present invention according to the
second embodiment is now explained with reference to the relevant
drawings. The components of the second embodiment which are the
same as those in the first embodiment are given the same reference
numerals, and the explanation thereof is omitted.
The difference between the seatbelt device of the second embodiment
and the seatbelt device of the first embodiment is in the structure
of the webbing locking mechanism 102B of the retractor 100B and the
controller 200B.
That is, the locking mechanism 102B of the second embodiment
comprises a compulsory unlocking mechanism 102a.
FIG. 24 shows an example of the compulsory unlocking mechanism
102a. The latch plate 71 constituting a part of the locking
mechanism 102B is mounted on the reel shaft 103a. Teeth are formed
on the outer periphery of the latch plate 71, and locking is
secured by the tip of the pole 72, wherein the center thereof is
rotatably supported by a frame (not shown), engaging with such
teeth. Normally, the locking operation is adequately controlled by
the emergency locking mechanism which is activated upon detecting
the webbing 302 (c.f. FIG. 1) exceeding a prescribed protraction
acceleration, the emergency locking mechanism which is activated
upon detecting an acceleration working on a vehicle exceeding a
prescribed value, or an automatic locking mechanism.
The compulsory unlocking mechanism 102a is provided with a pole
actuator 73 and is activated by activation signals from the
controller 200B. When the pole actuator 73 operates, as shown in
FIG. 25, the rod is extended to compulsorily extend the pole 72,
and the pole 72 is unlocked. Thereby, the reel shaft 103a is freed
and the protraction of the webbing is enabled.
FIGS. 26 and 27 show structural examples of the pole actuator 73.
Built in to the pole actuator 73 is a rod 73b provided with a
ratchet (teeth) on the inside of a cylinder 73a, and a gas
generator 73c is provided to the bottom face of this cylinder 73a.
Provided to the outlet of the cylinder 73a is a stopper 73d for
stopping the ratchet and preventing the rod 73b from returning.
When activation (ignition) signals from the controller 200B are
supplied to the gas generator 73c, as shown in FIG. 29, the powder
ignites and expansion gas is generated, and the rod 73b in the
cylinder 73a is pushed out. As shown in FIG. 25, the rod 73b
rotates the pole 72 and compulsorily unlocks the system.
Similar to the first embodiment, provided to the left end of the
reel shaft 103a are a pretensioner 104, pulley 105, and potential
meter 111.
Supplied to the controller 200B are the respective outputs from the
seatbelt device detector 317 for detecting the
engagement/disengagement of the seatbelt device, drowning detector
401 for detecting the drowning of a vehicle, rollover detector 402
for detecting the rollover of a vehicle, and collision predictor
403 for predicting the possibility of a collision between one's
vehicle and an obstacle.
As the drowning sensor 401, for example, a sensor capable of
detecting the capacitance change between the electrodes due to
water or seawater seeping therebetween may be used. The impedance
of this sensor is measured with an impedance-measuring device and,
when it is lower than a prescribed impedance value, the vehicle is
determined as having drowned. This drowning detector 401 is
arranged, for example, at the lower part of the vehicle interior at
the center console etc.
The rollover detector 402, for example, may be structured of a roll
angle sensor and a judgment unit. The roll angle sensor, for
example, may be structured by utilizing a distortion gauge
acceleration sensor for detecting the acceleration in the upward
and downward directions. The judgment unit judges a rollover when
the roll angle exceeds a prescribed value. For example, the
detection acceleration is 1G during the normal travelling of a
vehicle, but when the vehicle rotates its front and back directions
as the axial direction, it becomes 0.5 G at a 45-degree rotation.
Therefore, it is possible to judge a rollover by the change in the
gravitational value.
The collision predictor 403 measures the distance to the obstacle
with the likes of an infrared laser radar, millimeter wave radar,
or ultrasonic radar and calculates the time until collision by
dividing such obtained distance with the time variation amount
(speed) of such distance. If the time until collision is less than
a prescribed value, 0.1 second for example, the collision predictor
403 judges that a collision is unavoidable, and outputs collision
signals.
FIG. 20 is a block diagram explaining the outline of the structure
of the controller 200B. Similar to the first embodiment, this
controller 200B is structured of a microcomputer system. The CPU
201 loads the control program and data retained by the ROM 202 to
the work area of a RAM 203, implements various programs explained
later, and controls operations such as the compulsory unlocking of
the seatbelt locking mechanism, and the normal rotation, reverse
rotation, and suspension of the DC motor 110. The output voltage
corresponding to the rotation quantity of the aforementioned
potential meter 111 is A/D converted in a prescribed cycle by an
A/D converter of the input interface 204. The input interface 204
has a CPU built therein and writes the converted output voltage
data to the rotational field of the axis 103a of the RAM 203 by DMA
operation. The CPU also monitors the output voltage data. For
example, the CPU compares the values of the previous and present
output voltage data, judges the state of the reel shaft axis 103a,
namely the state of normal rotation, reverse rotation, or
suspension of rotation, and sets the corresponding flag to the flag
register of the RAM 203 by DMA operation.
The CPU of the input interface 204 sets a flag representing the
engagement/disengagement of the seatbelt device to a flag register
of the RAM 203 upon receiving the output of the seatbelt engagement
detector 317 built in the buckle of the seatbelt device and which
generates an output corresponding to the engagement of the
webbing.
The CPU of the input interface 204 sets a drowning flag to the flag
register of the RAM 203 upon receiving signals from the drowning
detector 401 representing that the vehicle has drowned.
The CPU of the input interface 204 sets a rollover flag to the flag
register of the RAM 203 upon receiving signals from the rollover
detector 402 showing the rollover of a vehicle.
The communication interface 216 is structured of a microcomputer
system and, when the collision predictor outputs collision signals,
sets a collision flag to the flag register of the RAM 203 by DMA
operation.
When the prescribed conditions set to the control program explained
later are fulfilled, the CPU 201 provides to the output interface
205 an unlocking order, and normal rotation order, reverse rotation
order, or suspension order of the DC motor 110. The output
interface 205 supplies activation signals (ignition signals) to the
gas generator 73c of the compulsory unlocking mechanism 102a in
correspondence with the unlocking order. The output interface 205
further generates gate control signals G1, G2 corresponding to the
normal rotation order, reverse rotation order, or drive suspension
order and controls the power transistor bridge circuit of the motor
drive circuit 206. The motor drive circuit 206 supplies to the DC
motor 110 normal direction drive current or reverse direction drive
current, or suspends such supply.
FIGS. 21 through 23 are flowcharts explaining the operation of the
CPU 201 of the controller 200B. The CPU 201 monitors the flag
register periodically or in accordance with the generation of
interrupt orders. The CPU 201 judges whether a collision flag has
been set to the flag register (S12). If the collision flag has been
set (S12; YES), the CPU 201 orders the output interface 205 to
retract the seatbelt for a predetermined time, 5 seconds for
example. Thereby, the DC motor 110 rotates the reel shaft 103a in
the webbing retracting direction, secures the passenger to his/her
seat by removing the slack in the webbing, and seeks the safety of
the passenger upon a collision (S14). If the collision flag has not
been set (S12; NO), the CPU 201 checks other flags.
Next, the CPU 201 judges whether a drowning flag has been set to
the flag register (S122). If a drowning flag has been set to the
flag register (S122; YES), in order to provide a certain degree of
slack to the seatbelt (30 cm for example) such that a passenger may
escape even if he/she is wearing the seatbelt, the CPU 201
activates the actuator 73 by supplying activation signals to the
compulsory unlocking mechanism of the seatbelt device of the
retractor 100B, compulsorily unlocks the webbing 302, and makes the
reel shaft 103a rotatable (S124). The CPU 201 orders the reverse
rotation (seatbelt protracting direction) of the DC motor 110 to
the output interface 205. When the DC motor 110 rotates, the CPU
201 detects the rotation quantity with the output of the potential
meter 111 and, when it becomes a prescribed quantity, orders the
suspension of the DC motor 110 to the output interface 205 (S126).
When a drowning flag has not been set to the flag register (S122;
NO), the CPU 201 checks other flags.
Next, the CPU 201 judges whether a rollover flag has been set to
the flag register (S132). When a rollover flag has been set to the
flag register (S132; YES), as the passenger is upside down due to
the rollover and there is fear that such passenger may hit his/her
head on the vehicle ceiling due to the impact of the rollover, the
CPU 201 does not protract the webbing until a predetermined time
elapses sufficient for the collision to abate from the time the
rollover is detected (S134). After the impact from the rollover has
abated, the CPU 201 provides activation signals to the compulsory
unlocking mechanism 102a and unlocks the reel shaft 103a by
activating the actuator 73 (S136). Next, the CPU 201 rotates the DC
motor 110 to the protracting side of the webbing 302. In order to
provide a certain degree of slack to the seatbelt (30 cm for
example) such that a passenger may escape even if he/she is wearing
the seatbelt, the CPU 201 orders the reverse rotation (seatbelt
protracting direction) of the motor to the output interface 205.
When the DC motor 110 rotates, the CPU 201 detects the rotation
quantity by the output of the potential meter 111 and orders the
suspension of the DC motor 110 to the output interface 205 when
such quantity reaches a prescribed quantity (S138). When a rollover
flag has not been set to the flag register (S132; NO), the CPU 201
checks other flags.
According to the seatbelt device of the second embodiment as
described above, the slack in the webbing 302 is removed prior to
the vehicle collision and the webbing 302 is loosened when the
vehicle has drowned, such that the passenger may easily escape.
Further, when the vehicle rolls over, the seatbelt is loosened
after the rolling and impact of the vehicle due to the rollover
have abated, and the passenger's safety and ease of escape from
danger is sought.
According to the second embodiment as mentioned above, when an
accident is detected, the webbing is loosened after the impact from
the accident has abated, and the passenger may easily escape from
the vehicle. Moreover, the control mode of loosening the webbing
302 is determined in correspondence with the state of the accident
(or the type of accident). For example, if it is a drowning
accident or rollover accident, it is advantageous as the webbing is
loosened in a separate, appropriate timing.
Although the second embodiment describes examples of drowning and
rollover as state of vehicle accidents, it is not limited thereto
and may be of other states of vehicle accidents.
As described above, the seatbelt device according to the second
embodiment secures the passenger to his/her seat upon removing the
slack in the seatbelt prior to the accident and, after the
accident, loosens the seatbelt in an appropriate timing in
correspondence with the state of the vehicle accident. Thus, it is
preferable in that the passenger's safety and ease of escape are
ensured.
(Third Embodiment)
The seatbelt device of the present invention according to the third
embodiment is now explained with reference to the relevant
drawings. The components of the third embodiment which are the same
as those in the previous embodiments are given the same reference
numerals, and the explanation thereof is omitted.
The difference between the seatbelt device of the third embodiment
and the seatbelt devices of the previous embodiments is in the
structure of the controller 200C of the retractor 100C.
Similar to the previous embodiments, the DC motor 110 of the
retractor 100C in the third embodiment is connected to the
controller 200C. The motor drive circuit 206 controls the rotation
of the DC motor 110 in accordance with the control signals from the
controller 200C.
As shown in FIG. 28, the controller 200C comprises a timer 417 for
measuring time and a non-volatile memory 421, and is connected to
the buckle connection detector 416 for detecting whether the tongue
plate of the seatbelt device is engaged with the buckle and for
detecting whether the tongue plate of the seatbelt device has been
disengaged from the buckle, and to the controller (MPU) 415
provided to the travelling state detector 420 for detecting the
travelling state of the passenger driven vehicle.
The controller 415 is connected respectively to the distance sensor
412 for measuring the distance between a vehicle and the object in
front of such vehicle, and a steering angle sensor 413 for
detecting the steering angle of the steering wheel.
FIG. 29 is a circuit diagram of the motor drive circuit 206.
Terminals P1 and P2 shown in FIG. 29 are input terminals of PWM
(Pulse Width Modulation) signals output from the controller 200C
and, for example, 20 kHz PWM signals are input thereto. Terminals
P3 and P4 are output terminals for the current detector, and
terminals P5 and P6 are output terminals for the voltage detector.
Terminals P1 through P6 are respectively connected to the
controller 200C. Voltage Vb shown in FIG. 29 is supplied to the DC
motor 110. The plurality of transistors and FETs etc. shown in FIG.
29 are for driving the DC motor 110 in a normal rotation or reverse
rotation by PWM signals from the controller 200C.
Circuit C1 shown in FIG. 29 is a current detection circuit for
detecting the current i flowing to the DC motor from the current
flowing to the resistance r1, and comprises interface (IF) circuits
IF1 and IF2 for removing the fluctuation of the current due to the
influence of PWM signals. The controller 200C receives voltage
signals respectively from IF1 and IF2, and detects the current i
flowing to the DC motor 110 based on such voltage signals.
Circuit C2 is a voltage measurement circuit for measuring the
voltage between terminals applied to the DC motor 110 and comprises
IF3 and IF4 for removing the fluctuation between the terminals due
to the influence of PWM signals. The controller 200 receives
voltage signals respectively from IF3 and IF4 and measures the
voltage between the terminals applied to the DC motor 110 based on
such voltage signals.
IF1 through IF4 are, for example, a low-pass filter structure made
from a resistance r2, a resistance r3 having a resistance value
smaller than the resistance r2, and a condenser C3, and sets its
cutoff frequency to, for example, 20 Hz. Thereby, the influence of
PWM signals output to the controller 200C at the current detection
circuit C1 and voltage measurement circuit C2 is reduced to -60 dB.
Thus, the current to be detected by the current detection circuit
C1 and the voltage between the terminals to be measured by the
voltage measurement circuit C2 are hardly influenced.
The controller 200C judges whether the webbing 302 has been
protracted by the polarity of the voltage between the terminals of
the DC motor 110, and judges whether the retraction of the webbing
302 has been completed by the current i flowing to the DC motor
110.
Further, when the protraction of the webbing upon the passenger
fastening his/her seatbelt device is detected, the controller 200C
performs the following control operations: seatbelt fastening
assistance control for controlling the motor such that the webbing
302 can be easily protracted; seatbelt oppression removal control
for retracting the webbing 302 after the tongue plate of the
webbing is engaged with the buckle and controlling the motor in
order to provide a prescribed slack to the passenger after the
webbing 302 is fitted to the passenger's body and reaches a
retraction limit; movement control for controlling the DC motor 110
in order to ease the protraction of the webbing 302 when the
passenger tries to protract the webbing 302 such that he/she may
move after fastening such webbing; and housing control for
controlling the DC motor 110 in order to house the webbing 302 when
the passenger does not fasten the webbing 302 or when the tongue
plate is disengaged from the buckle.
The flow of the control signals of the respective constituent parts
structuring the seatbelt device of the third embodiment is now
explained.
The distance sensor 412 outputs to the controller 415 control
signals showing the measurement results of the distance between
one's vehicle and the object in front of such vehicle. The
controller 415 calculates the safe vehicle interval distance from
the formula (1) below and, when the safe vehicle interval distance
ds is larger than the value output from the distance sensor 412,
outputs to the controller 200C control signals showing a collision
danger warning.
After storing to the non-volatile memory 421 the number of times
the control signals show this collision danger warning (i.e.,
frequency of control signals), the controller 200C performs the
collision danger warning control for alternately protracting and
retracting the webbing 302 in a repetitive manner. Thereby, the
passenger will recognize that there is a danger of collision.
Furthermore, the controller 415 calculates a collision unavoidable
distance dd obtainable from the formula (2) below and, when this
collision unavoidable distance dd is larger than the value output
from the distance sensor 412, outputs to the controller 200C
control signals showing that a collision is unavoidable. At such
time, the controller 200C performs collision unavoidable control
for changing the retraction power of the webbing 302 in accordance
with the value output from the distance sensor 412 and retracting
the seatbelt thereafter. The passenger is thereby appropriately
protected upon a collision.
The steering angle sensor 413 outputs to the controller 415 control
signals corresponding to the steering angle of the steering wheel.
When the maximum value of the variation amount of the steering
angle within a predetermined time (2 seconds for example) is within
a prescribed value (8 degrees for example), the controller 415
judges that there is an indication of the driver driving asleep and
outputs to the controller 415 control signals showing a warning
thereof. After storing the frequency of sent control signals
showing this sleep-driving warning to the non-volatile memory 412,
the controller 415 performs sleep driving prevention control for
alternately protracting and retracting the seatbelt in a repetitive
manner. The driver may thereby recognize that he/she was driving
asleep.
The buckle connection detector 416 detects whether the tongue plate
of the seatbelt device is engaged with the buckle, and outputs
corresponding control signals to the controller 200C. The motor
drive circuit 206 controls the rotation of the DC motor 110 based
on the control signals from the controller 200C.
FIG. 30 is a diagram showing an example of control programs
executed by the controller 200C. Included in the control programs
executed by the controller 200C are: program 430 for setting the
alarm threshold, program 431 for detecting the protraction speed,
program 432 for detecting the time until seatbelt engagement,
program 433 for detecting the frequency of protraction during
seatbelt engagement, program 434 for detecting the danger
encountering frequency, program 435 for detecting the continuation
time of seatbelt engagement, and program 436 for detecting the
seatbelt engagement frequency.
The program 430 for setting the alarm threshold is a program for
setting the alarm threshold regarding whether to give a warning
with the vibration of the seatbelt device which alternately
protracts and retracts the webbing 302 in a repetitive manner. It
is easier to send the warning with the vibration of the seatbelt
device by lowering the alarm threshold, and it will be more
difficult to send the warning with the vibration of the seatbelt
device by raising the alarm threshold. For example, when a
passenger is wearing the seatbelt for a prolonged period of time,
the alarm threshold is lowered in order to send, with ease, the
warning with the vibration of the seatbelt device as the driver's
attentiveness lowers due to fatigue from driving for many
hours.
The program 431 for detecting the protraction speed is a program
for detecting the protraction speed of the webbing 302 when the
passenger fastens the seatbelt device from an unfastened state.
Particularly, this program detects the protraction speed of the
webbing 302 based on the level of the voltage between the terminals
of the DC motor 110.
The program 432 for detecting the time until seatbelt engagement is
a program for detecting the time from the moment the protraction
stops upon the webbing 302 being protracted when the passenger
fastens the seatbelt device from an unfastened state until the time
the seatbelt device is fastened. Particularly, the protraction
stoppage of the webbing 302 is determined by the voltage between
the terminals of the DC motor 110, and the engagement of the
seatbelt device is detected by the control signals from the buckle
engagement detector 416. This program clocks with the timer 417 the
time from the moment the protraction of the webbing 302 stops until
the time the seatbelt device is fastened, and performs the
detection thereof.
When the protraction speed detected by the program 431 for
detecting the protraction speed is fast and when the time until
engagement of the seatbelt device detected by the program 432 for
detecting the time until seatbelt engagement is short, the
controller 200C judges that the driving ability of the passenger is
high, and makes the warning difficult by raising the alarm
threshold with the program 430 for setting the alarm threshold.
The program 433 for detecting the frequency of protraction during
seatbelt engagement is a program for detecting the frequency of the
webbing protraction by the passenger during the fastening of the
seatbelt device. Specifically, a single protraction is when the
webbing 302 is protracted and a stoppage thereof is detected
thereafter. This frequency of webbing protraction is calculated
during the continuous engagement of the seatbelt, and continued
until the seatbelt device becomes an unfastened state. This program
detects the continuation time during the engagement of the seatbelt
device with the timer 417, detects the protraction frequency by
dividing the calculated webbing 302 protraction frequency with this
detected continuation time of seatbelt engagement, and stores this
frequency to the non-volatile memory 421.
When the protraction frequency detected by the program 433 for
detecting the frequency of protraction during seatbelt engagement
is high, the controller 200C judges that there is a high
possibility of encountering danger, and eases the warning by
lowering the alarm threshold with the program 430 for setting the
alarm threshold.
The program 434 for detecting the danger encountering frequency is
a program for calculating the frequency of danger encountered by
the passenger while wearing the seatbelt device, and detecting the
danger encountering frequency by dividing such calculated frequency
with the continuation time of seatbelt engagement during the
engagement of the seatbelt device. Moreover, the frequency of
danger encountered by the passenger while wearing the seatbelt
device is the aggregate value of the frequency of the control
signals showing the collision danger warning is sent and frequency
of the control signals showing the sleep-driving warning stored in
the non-volatile memory 421. The detected danger encountering
frequency is stored in the non-volatile memory 421.
When the danger encountering frequency is high, the controller 200C
lessens the amount of slack in the webbing 302 provided during the
engagement of the seatbelt device than usual, or increases the
tension of the webbing 302 to further secure the passenger. The
controller 200C further increases the retraction power of the
webbing 302 upon encountering danger, and controls the drive of the
DC motor 110 so as to increase the vibration frequency of the
seatbelt device with the vibration alarm of the seatbelt device.
The control of the drive of the DC motor 110 is conducted with the
change in the duty ratio of PWM signals input to the motor drive
circuit 206 from the controller 200C.
The program 435 for detecting the continuation time of seatbelt
engagement is a program for detecting the continuation time of
seatbelt engagement during the engagement of the seatbelt device
clocked by the timer 417. In this program, if the time elapsed from
the unfastened state of the seatbelt device to the fastened state
of the seatbelt device is under a prescribed value, it is possible
to clock the time by accumulating the previous continuation time of
seatbelt engagement during the engagement of the seatbelt
device.
As the passenger's attentiveness lowers due to fatigue from driving
for many hours when the continuation time of seatbelt engagement
during the engagement of the seatbelt device is prolonged, the
controller 200C eases the warning by lowering the alarm threshold
with the program 430 for setting the alarm threshold.
The program 436 for detecting the seatbelt engagement frequency is
a program for detecting the frequency of the seatbelt device being
fastened from an unfastened state based on the control signals
output from the buckle connection detector 416. The frequency
detected in this program is accumulated and added to the previous
frequency and stored in the non-volatile memory 421.
As the webbing 302 becomes difficult to retract due to the
deterioration and the like of the webbing as the frequency stored
in the non-volatile memory 421 gradually increases, the controller
200C controls the drive of the DC motor 110 in order to increase
the retraction power of the webbing 302. The control of the drive
of the DC motor 110 is conducted with the change in the duty ratio
of PWM signals input to the motor drive circuit 206 from the
controller 200C.
According to the third embodiment as mentioned above, based on the
results detected respectively from the program 430 for setting the
alarm threshold, program 431 for detecting the protraction speed,
program 432 for detecting the time until seatbelt engagement,
program 433 for detecting the frequency of protraction during
seatbelt engagement, program 434 for detecting the danger
encountering frequency, program 435 for detecting the continuation
time of seatbelt engagement, and program 436 for detecting the
seatbelt engagement frequency, the slack in the webbing 302 is
reduced than usual, the tension of the webbing 302 is increased,
the retraction power of the webbing 302 is increased, the vibration
cycle of the seatbelt device during the alarm generated by the
vibration of the seatbelt device is shortened, the drive of the DC
motor 110 is controlled and the alarm threshold is controlled in
order to ease the alarm by lowering the threshold or making the
alarm difficult by raising the threshold. Thus, it is possible to
provide a comfortable seatbelt-wearing environment and to
adequately secure and protect the passenger.
(Fourth Embodiment)
The seatbelt device according to the fourth embodiment of the
present invention is now explained with reference to the relevant
drawings.
FIG. 31 is a diagram showing the structure of the retractor of the
seatbelt device according to the fourth embodiment.
The components of the fourth embodiment which are the same as those
in the third embodiment are given the same reference numerals, and
the explanation thereof is omitted.
The controller 200D of the retractor of the seatbelt device
according to the fourth embodiment, as shown in FIG. 31, connects
to the controller 200C of the retractor 100C of the third
embodiment the later explained user selector 441, alarm threshold
setting unit 442, slack setting unit 443, vibration pattern setting
unit 444, and retraction power setting unit 445. Therefore, as the
structure of the retractor other than the user selector 441, alarm
threshold setting unit 442, slack setting unit 443, vibration
pattern setting unit 444, and retraction power setting unit 445 are
the same as those in the third embodiment, the explanation thereof
is omitted.
The user selector 441 is provided with a user selection switch, and
when the passenger selects himself/herself with this user selection
switch, the various prescribed values set in advance per passenger
are restored in the non-volatile memory 421 as one's own setting
values. Various prescribed values are, for example, the alarm
threshold, webbing slack, vibration pattern of the seatbelt device
during the alarm generated by the vibration of the seatbelt device,
and retraction power of the webbing.
The alarm threshold setting unit 442 enables the passenger to
freely set the alarm threshold; provided that the alarm threshold
is set within a prescribed range.
The slack setting unit 443 enables the passenger to freely set the
slack in the webbing 302 after fastening the seatbelt; provided
that the slack in the webbing is set within a prescribed range.
The vibration pattern setting unit 444 enables the passenger to
freely set the vibration pattern of the seatbelt device by the
alarm generated by the vibration of the seatbelt device; provided
that there are three selectable vibration patterns, namely, a
vibration pattern in which the vibration cycle is accelerated, the
vibration is intensified, or the vibration duty is increased (i.e.,
retraction time per cycle is prolonged).
The retraction power setting unit 445 enables the passenger to
freely set the retraction power of the seatbelt; provided that the
retraction power of the seatbelt is set within a prescribed
range.
According to the fourth embodiment as mentioned above, with the
user selector 441, alarm threshold setting unit 442, slack setting
unit 443, vibration pattern setting unit 444, and retraction power
setting unit 445, it is possible to set one's optimum alarm
threshold, webbing slack, vibration pattern of the seatbelt device
during the alarm generated by the vibration of the seatbelt device,
and retraction power of the webbing. Thus, it is possible to
provide a comfortable seatbelt-wearing environment and to
appropriately secure and protect the passenger.
* * * * *